Noise is a problem in many communication schemes and comes in a variety of forms. For example, lightning, sparks, etc., can electromagnetically interfere with communication signals in the Radio Frequency (RF) spectrum. Short burst-like electromagnetic radiation can interfere with communication signals over a broad range of frequencies and is commonly referred to as impulsive noise. Other forms of noise include continuous wave (CW) electromagnetic radiation, such as that occurring with other communication signals located on the same RF frequency. In any case, random noise is ever present and represents a basic challenge to communications engineers.
As communication techniques become more complex (e.g., to satisfy higher data consumption), communication signals can become more susceptible to noise. In the cable television industry, upstream noise (e.g., from households) is problematic because it can affect other households. For example, suppose one cable modem (a.k.a. a customer premise equipment, or “CPE”) at one household is experiencing a bad connection that allows noise to leak into the CPE's connection to a network node. That noise can affect other CPEs connected to the network node. And, the CPE needs to use more power to overcome the noise.
Generally, there are many CPEs (e.g., hundreds) coupled to a node. When a CPE is continually “noisy” on the upstream link, the CPE can be more easily located and corrected. However, when the connection is intermittent, it is very difficult to determine which CPE is causing the noise on the upstream link. And, sending repair teams to correct problems that are difficult to find and identify is a costly proposition. For example, when hundreds of CPEs are connected to a cable television node, a cable television repair service may be forced to search each of the CPEs to identify and repair a problem associated with one CPE.